Drought alters the physiological quality of runner-type peanut seeds during seed formation

Authors: MORENO, LETICIA - University Of Georgia; Lamb, Marshall; BUTTS, CHRISTOPHER - Retired ARS Employee; Sorensen, Ronald - Ron; TUBBS, R - University Of Georgia; MONFORT, W - University Of Georgia; GREY, TIMOTHY - University Of Georgia; PILON, CRISTIANE - University Of Georgia

Submitted to: Environmental and Experimental Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/13/2024
Publication Date: 10/15/2024
Citation: Moreno, L., Lamb, M.C., Butts, C.L., Sorensen, R.B., Tubbs, R.S., Monfort, W.S., Grey, T.L., Pilon, C. 2024. Drought alters the physiological quality of runner-type peanut seeds during seed formation. Environmental and Experimental Botany. Volume 228, Part B. https://doi.org/10.1016/j.envexpbot.2024.106009.
DOI: https://doi.org/10.1016/j.envexpbot.2024.106009

Interpretive Summary: A 3-year study to determine the effect of drought on the quality of the resulting peanut seed was conducted. Each year, two stress regimes were induced: a fully-irrigated control and a drought-stressed regime. The drought-stressed regime was implemented by withholding all water for 30 days beginning 80 days after planting. The cultivar Georgia-06G was used for the duration of the study. Peanuts were dug each year after accumulating 2500 growing degree days. The harvested pods were classified into maturity classes according to the hull-scrape method. The seed from each maturity class and stress treatment were tested for germination percentage, vigor, dessication tolerance, and longevity. Maximum germination occurred in the brown maturity classification for both water stress levels. In water-stressed seed, the maximum dessication tolerance occurred in less mature seed than in well-watered seed. In general, drought stress promoted greater peanut seed quality than in well-watered production.

Technical Abstract: Sub-optimal water supply during crop development, especially during peak flowering and pod filling, affects the quality of the seeds produced, generally resulting in poor seed quality. The goals of this study were to identify the acquisition pattern of the physiological seed components and to assess the impact of drought during seed development on seed physiological quality in peanut. The research was conducted at the USDA-ARS National Peanut Research Laboratory in Dawson, GA for three consecutive years (2019, 2020, and 2021) using field conditions under two water regimes, well-watered control and drought stress. Rainout shelters were used to prevent rain in the drought-stressed block for 30 d, starting 80 d after planting. The well-watered block received supplemental irrigation when soil water potential reached -40 kPa. Peanut pods from the cultivar Georgia-06G were harvested at 2500 growing degree days, and the peanut maturity profile board was used to classify the pods into different maturity classes. Germination, vigor, desiccation tolerance (DT), and longevity tests were performed on seeds from each maturity class and both water regimes. The acquisition pattern for the physiological components of seed quality was developed for seeds grown under well-watered and drought conditions. Maximum germination occurred in ‘brown 1’ and ‘brown 2’ under drought and well-watered conditions, respectively. Both water regimes reached maximum vigor in the 'brown 1'; however, under well-watered conditions, vigor had a rapid decline after ‘brown 1’ while under drought stress, the decline in vigor was slower. Maximum DT was achieved between ‘orange’ and ‘brown 1’ under drought conditions, whereas under well-watered conditions, maximum DT was achieved between ‘brown 2’ and ‘black 1’. Seeds from immature classes had lower capacity to be stored compared with mature seeds. Overall, drought stress promoted greater physiological quality in the peanut seeds than the well-watered treatment. Maximum physiological quality was achieved in the transition from ‘orange’ into ‘brown 1' under drought conditions, and in the transition from ‘brown 2’ to ‘black 1’ class under well-watered conditions. Also, drought stress preserved seed quality for a longer period.